This invention relates to a single piece push-pull dispenser container closure which is opened and closed by moving the push-pull dispenser longitudinally along the container neck permitting the container contents to be poured without removing the push-pull dispenser closure from the container.
Push-pull dispensers are known in the art, have been employed in a wide variety of products from water and juice bottles, to condiment and detergent bottles, and have gained wide acceptance in the marketplace. Their wide acceptance and usage are the results of several important advantages over traditional non-dispensing closures. Notably, push-pull dispensers permit the container to be opened and closed without removing or separating any portion of the push-pull dispenser from the container. Thus, the container can usually be held and the push-pull dispenser opened and closed with one hand. Further, since the push-pull dispenser is not removed when opening and closing the container it is unlikely to be lost or misplaced. These features of push-pull dispensers are particularly advantageous for single serving beverage containers wherein the user can drink directly from the dispenser, using only one hand or their mouth to open and close the container while exercising, driving or engaging in like activity.
The known push-pull dispenser closures are constructed from two interlocking pieces, a bottom piece attached to the container neck and a top piece slidably engaging the bottom piece. The bottom piece comprises a donut-shaped top having a center hole, an upwardly depending annular skirt along the periphery of the hole, and a downwardly depending annular skirt from the perimeter of the top. The downwardly depending annular skirt is adapted with a securement means such as threads or the like for securing the closure to the container neck. Disposed within the upwardly depending annular skirt is an elevated cylinder which is joined by connectors therebetween. The outside wall of the elevated cylinder and the inside wall of the upwardly depending skirt define a donut-shaped orifice in the bottom piece.
The top piece comprises an annular skirt having upper and lower portions and acts as a cap over the donut-shaped orifice of the bottom piece. The upper portion has an orifice sized to engage the elevated cylindrical portion of the bottom piece. The lower portion is sized to fit over and slidably engage the upwardly depending skirt of the bottom piece whereby it can be raised and lowered. In its lower, closed position, the elevated cylinder plugs the orifice of the top piece preventing release of the container contents. In the upper, open position, the elevated cylinder disengages the orifice of the top piece, permitting the fluid to flow through the donut-shaped orifice of the lower piece and out the orifice in the top piece.
Although the push-pull dispensers of this known design have gained wide acceptance and usage, and provide several advantages over conventional non-dispensing closures, these advantages are realized at a higher cost and some loss of function. Manufacturing costs are higher, in comparison with conventional non-dispensing closures due to the two piece construction of known designs. Function is lost in that the fluid flow orifice of known push-pull dispensers is necessarily smaller than the fluid flow orifice defined by the mouth of the container. The smaller orifice results in lower flow rates. Further, the small diameter of the orifice results in flooding of the outlet orifice. Flooding of the outlet orifice prevents back flow of air into the container to replace the dispensing liquid. When the back flow of air is restricted, a negative pressure or a vacuum develops inside the container, inhibiting or preventing outward flow of the container contents. In this respect, containers sealed with known push-pull dispensers ordinarily require that the user either squeeze the container to increase the pressure inside the container or frequently tip the container upright to permit the back flow of air into the container.
For the foregoing reasons, there is a need for a push-pull closure which is cheaper to manufacture, provides increased flow rates and alleviates vacuum formation.